Telescopes/Transcript
Transcript Text reads: The Mysteries of Life with Tim and Moby Tim looks through a telescope from his window and sees Moby, bouncing a balloon on top of his head. Moby waves at Tim. Tim seems confused. Tim reads from a typed letter. TIM: Dear Tim and Moby, how does a telescope let you see things far away? From, Eugenie. Ahhm. The moon is about a quarter the size of the earth. But because it's so far away, it looks pretty small. Tim looks up at the moon from his backyard. TIM: We can see it because light reflected off of it focuses a small spot of light on your eye's retina. An animation shows the light from the moon shining on Tim’s eye. The light reflects off his retina. TIM: From where we stand, it just looks like a little glowing yellowish-white circle. Moby looks at the moon through a telescope. MOBY: Beep. TIM: With a good enough telescope, you can see much more detail; craters and mountains and stuff. A view of the moon through Moby's telescope shows the details that Tim describes. MOBY: Beep. TIM: Telescopes capture and magnify light. As you can see in this simple telescope, a large lens in the opening collects the light bouncing off of a faraway object and focuses it at a point inside the body of the telescope. Then a smaller lens in the telescope's eyepiece magnifies that focused light and projects it into your eye. Since the light has been magnified, the image takes up much more of your eye's retina and you see more detail. That's a refractor telescope, one that uses glass lenses to gather light. An animation illustrates how a refractor telescope focuses light and projects it into the eye. The image appears larger through the process Tim describes. TIM: There's another kind, a reflector telescope, which uses a series of curved mirrors to gather and focus light. Light comes through the opening and is reflected by a curved mirror onto a second mirror, which reflects the light into your eye. An animation illustrates how light is focused and reflected in the telescope by a series of curved mirrors, then reflected into the eye. TIM: Some telescopes are better at collecting light than others. An image shows a small and large telescope. TIM: The aperture of a telescope is the diameter of the lens or mirror that gathers light. The larger the aperture, the more light the telescope can focus, and the brighter the final image. An image shows two different sized telescope lenses. The width of the aperture is indicated by an arrow across the center of each lens. The larger lens reveals a brighter image than the smaller one. TIM: Magnification is the telescope's ability to enlarge an image. An animation shows a telescope zooming in on the moon. TIM: Magnification is handled by the eyepiece, and it depends on the combination of lenses used. An animation shows two different lenses combining and magnifying the image of the moon. MOBY: Beep. TIM: Well no, there are many different types of telescopes. Optical telescopes include the simple handheld ones that pirates use, and binoculars, which are really just two telescopes stuck together so you can see in stereo. There are also giant telescopes like the Keck Observatory in Hawaii, and the Hubble Space Telescope, which operates from Earth orbit where its images can be free of the distorting effects of Earth's atmosphere. Images show a simple telescope, a pair of binoculars, the giant telescope in Hawaii, and the space telescope that Tim describes. TIM: All optical telescopes magnify visible light, so it's stuff you can see with the human eye. But there are other important types of telescopes that see in other kinds of electromagnetic radiation. Radio telescopes see in radio waves. Radio telescopes can be used alone or together with other radio telescopes to study things like stars and other really distant space objects. They're also used to collect data from satellites and space probes. Side by side images show a single radio telescope, and a row of radio telescopes. TIM: Other telescopes collect things like X-rays, gamma rays, and infrared light, mostly from stuff that we just can't see with visible light. Moby's eyes extend outward and become telescopic. He begins to walk around. MOBY: Beep. TIM: Hey, hey be careful. Moby trips and crashes to the ground. TIM: Ohhh! Category:BrainPOP Transcripts